and bush took the leadership, but he had democrats really supporting him. now you've got president obama taking the lead, taking this to a new level and he's got strong republican support. so even though it's kind of exceptional, it's really made a huge difference that everyone's come together to have the u.s. lead the way. >> you are incredibly focused on the issue of giving. you have pledged along with warren buffett and mark zuckerberg to give a majority of your wealth to philanthropy. forbes lists you as the richest person in america at $72 billion. a lot of people ask this question. have you decided how much you are going to leave to your children? >> well, certainly melinda and i think that kids starting off with $1 billion or some huge -- any huge amount of wealth is not necessarily in their interest as well as in the interest of society, and so the vast majority of our money will go to the foundation and we are putting all our energies into making sure that money is well spent and has a big impact, including giving to things like the global fund. >>